in cases like these, I find a task for myself. Maybe I linger near the front and say "oh coats go over here" (not that we have a need for coats this time of year) or "the bathroom is that way", whatever, if I have a task, I am in a role and can do much better than if I'm just cut loose to mingle. I hate things like this with a passion. but go, fake it a bit, and also decide going in what time you can leave, then you have an exit point (and you may find you want to stay a bit longer)